What is the origin of the term ‘pros and cons’?

The phrase ‘pros and cons’ is an abbreviation of the Latin phrase pro et contra, ‘for and against’, and has been in use in the abbreviated form since the 16th century, according to the Oxford English Dictionary.

‘Pros and cons’ is a well-established standard usage; Oxford’s larger dictionaries do not mark it as ‘informal’ or in any way restricted in use. The much longer alternative is the phrase ‘arguments for and against’.